Lighting apparatuses in greenhouses are important. The higher the lumen output the better for the growing plant. Ideally, one wants to keep the light as close to the plant as possible. However, the bulbs not only emit light, they also emit heat, which can damage plants. Therefore, a delicate balance has to be struck between how close the lighting devices are placed to the plant.
To maximize light output in a particular direction from a bulb that emits light in a 360 degree manner reflectors are used. However, the more times the light hits a reflector before it gets to the plant, the larger the distance the light is traveling. This results in a lower lumen output by the time it reaches the plant.
Prior art lighting reflectors radiate a lot of heat through the glass cover. This prevents a user from placing the lighting device too close to the plants. To cut down on radiated heat, typical lighting devices are air cooled by blowing air through one side of the device, over the light and out through the other side.